Comment 13 for bug 1372438

Reviewed: https://review.openstack.org/128642
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=acb37285ccdd9caa3133188b738ae09fa1bc5913
Submitter: Jenkins
Branch: stable/icehouse

commit acb37285ccdd9caa3133188b738ae09fa1bc5913
Author: Vivekanandan Narasimhan <email address hidden>
Date: Tue Sep 23 02:25:16 2014 -0700

    Race for l2pop when ports go up/down on same host

    With l2pop enabled, race exists in delete_port_postcommit
    when both create/update_port and delete_port deal with
    different ports on the same host, where such ports are
    either the first (or) last on same network for that host.
    This race happens outside the DB locking zones in
    the respective methods of ML2 plugin.

    To fix this, we have moved determination of
    fdb_entries back to delete_port_postcommit and removed
    delete_port_precommit altogether from l2pop mechanism
    driver.

    Icehouse changes:
    - dropped DVR related changes;
    - L2populationMechanismDriver does not have attribute
      L2populationAgentNotify.
    - some minor pep8 changes.

    Conflicts:
     neutron/plugins/ml2/drivers/l2pop/mech_driver.py
     neutron/plugins/ml2/plugin.py
     neutron/tests/unit/ml2/drivers/test_l2population.py

    Closes-Bug: #1372438
    Change-Id: If0502f57382441fdb4510c81a89794f57a38e696
    (cherry picked from commit 3cd2163d5105faad389bee5175ef446f0bb90289)